It seems that every passing day brings still more news of the government investigating, suing, indicting, or otherwise getting really tough with a hedge fund manager, employee, or somebody doing business with one of them. It might seem, if you don’t look very closely, that hedge funds are under a great deal of rigorous scrutiny from the people charged with keeping the markets safe for investors.

They’re not—but it certainly looks that way.

Oh, sure, there have been enough criminal proceedings to keep lawyers busy for years to come. At the federal courthouse in Brooklyn, former hedge fund executives at Bear Stearns are awaiting a jury verdict on charges of lying to investors about the health of their funds. Across the river in Manhattan, an ever-widening insider-trading scandal has been unfolding, involving employees of a New York hedge fund called the Galleon Group, including its billionaire CEO Raj Rajaratnam. On Monday, yet another embarrassing hedge-fund-related scandal took another turn of the screw. A former Securities and Exchange Commission enforcement lawyer, Robert Miller, pleaded guilty to conspiracy and securities fraud for participating in the Marc Dreier fraud scheme.

Dreier didn’t run a hedge fund himself, but he pleaded guilty to selling $700 million in bogus promissory notes to hedge funds. Even though the hedge funds were victims in this instance, their image was bruised just the same. The Dreier scandal added to the general aura of hedge funds as a less-than-savory business, prone to taking excessive risks that turn sour, and generally being up to no good. Bernie Madoff, while not running a hedge fund in the strict sense of the word, came close enough to the general description to be viewed as a “hedge fund manager” in the eyes of the media and public.

The problem is that none of these criminal investigations and prosecutions have any effect on the elephant in the room, which is that hedge funds—a significant asset class, with net assets believe to exceed $2.5 trillion—are almost entirely devoid of meaningful regulatory oversight. So little is known about them that even the size of the industry is not known for sure.

This laissez-faire attitude is remarkable in light of all that we’ve been through in recent years—or perhaps not remarkable at all, given the history of securities regulation.

To be sure, hedge funds had no significant, direct role in credit crunch or recent financial collapse. Some hedge fund managers, such as John Paulson and David Einhorn, recognized the excesses of credit mania earlier than anyone in government. But that’s no great comfort. If the Great Meltdown of 2008 taught us anything, it’s that no potential source of systemic risk must be overlooked. And hedge funds have been overlooked for a good many years.